<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <meta name="author" content="甘忠祥">
    <title></title>
    <style>
        .container{
            width: 1000px;
            margin: 100px auto;
        }
        ul{
            list-style: none;
        }
        a{
            color: white;
            text-decoration: none;
        }
        .list{
            width: 1000px;
            height: 60px;
             background-color: gray; 
            /* display: flex;
            justify-content: space-around; */
        }
        .list>li{
            float: left;
            width: 240px;
            color: white;
            line-height: 60px;
            height: 60px;
            /* width: 150px; */
            background-color: gray;
            text-align: center;
            /* margin-right: 40px; */
        }
        .info{
            border: 1px solid black;
            color: gray;
            width: 100px;
            margin-left: 30px;
        }
        .info a{
            color: gray;
            text-decoration: none;
        }
    </style>
</head>

<body>
    <div class="container">
        <ul class="list">
            <li><a href="">公司简介</a>
                <ul class="info">
                    <li><a href="">概况简介</a></li>
                    <li><a href="">发展历史</a></li>
                    <li><a href="">联系我们</a></li>
                    <li><a href="">人才招聘</a></li>
                </ul>
            </li>
            <li><a href="">产品介绍</a>
                <ul class="info">
                    <li><a href="">概况简介</a></li>
                    <li><a href="">发展历史</a></li>
                    <li><a href="">联系我们</a></li>
                    <li><a href="">人才招聘</a></li>
                </ul>
            </li>
            <li><a href="">联系我们</a>
                <ul class="info">
                    <li><a href="">概况简介</a></li>
                    <li><a href="">发展历史</a></li>
                    <li><a href="">联系我们</a></li>
                    <li><a href="">人才招聘</a></li>
                </ul>
            </li>
            <li><a href="">人才招聘</a>
                <ul class="info">
                    <li><a href="">概况简介</a></li>
                    <li><a href="">发展历史</a></li>
                    <li><a href="">联系我们</a></li>
                    <li><a href="">人才招聘</a></li>
                </ul>
            </li>
        </ul>
    
<script src="./jquery.min.js"></script>
</body>
<script>
    $('.info').css('display','none');
     $('.list>li').mouseenter(function(){
        var index = $('.list>li').index(this);
        $('.list>li>a').eq(index).css('color','orange').css('text-decoration','underline')
        $('.info').eq(index).css('display','block')
        $('.info a').mouseenter(function(){
            var index1 = $('.info a').index(this);
            $('.list>li>a').eq(index).css('color','white').css('text-decoration','none')
            $('.info a').eq(index1).css('text-decoration','underline')
        })
        $('.info a').mouseleave(function(){
            var index1 = $('.info a').index(this);
            $('.info a').eq(index1).css('text-decoration','none')
        })
    });
    $('.list>li').mouseleave(function(){
        var index = $('.list>li').index(this);
        $('.list>li>a').eq(index).css('color','white').css('text-decoration','none')
        $('.info').eq(index).css('display','none');
    });
</script>
</html>